The present invention relates to a display method and a display apparatus, more particularly, to a display method and a display apparatus, in which consideration is given so as to allow recognition of meaning of differences in the original colors even in the case of displaying color information on a monochrome display (a display apparatus capable of displaying a gray scale).
In recent years, a system applying a computer has been constructed in various fields and improvement in work efficiency is being promoted. Similar tendency can be seen in the healthcare field. Establishment of on-line systems for clerical work and data concerning medical care is promoted in medical facilities regardless of the scale, from small clinics to large hospitals. The above data concerning medical care include image data, and a system is established in medical facilities that enables the image data on results of various examinations to be searched and referred to at each computer terminal of the system.
In this case, some problems have been pointed out. One of the problems is that a sense of incongruity arises between a conventional image on a photograph film (hereinafter simply referred to as a film) and a display image on an electronic display apparatus (hereinafter simply referred to as a display apparatus) in a field such as X-ray imaging where recording has been performed by the use of the film and there exists not only a huge storage of data relating to X-ray images recorded on films but also accumulation of many years experience in observation and evaluation thereof (diagnosis by a doctor).
Also, another problem is whether the meaning of the differences in the original colors is identifiable or not in the case of displaying color information (which is not always an image) on a display apparatus for displaying monochrome images such as an X-ray image and capable of displaying a gray scale (in X-ray photographs, an image is recorded on the film using a blue base, but it is essentially a monochrome image). In the following, detailed descriptions will be made for these problems.
First of all, the first case will be described where the image conventionally observed and evaluated as an image on a film is digitalized(electronized? computerized?) by some kind of method and displayed on a display apparatus.
As widely known, in the image recorded on a film, amount of X-ray irradiation (strictly speaking, the amount of the X-ray reaching the film through a subject) and optical density of the film (logarithmic value) are approximately proportional to each other.
In contrast, a direct proportionality within a certain range is generally established between input and output of a display apparatus, so that mere digitalization of the image recorded on a film results in an image which causes the sense of incongruity as described above. Specifically, the proportionality in terms of the logarithmic values is established on one hand, and the direct proportionality is established on the other hand; therefore, the resulting image causes the sense of incongruity to an observer.
To cope with this problem, methods have been proposed in which, when simply digitalizing the image recorded on a film, data conversion is carried out upon displaying the digitalized image on a display apparatus or in which digitalization suitable for displaying on a display apparatus is carried out from the beginning. As a specific example of apparatus embodying the former method, the image display apparatus disclosed in the gazette of JP 11-174992 A can be presented.
Meanwhile, with respect to the problem of identifiability of the differences in the original colors in the case of displaying color information on the display apparatus capable of displaying a gray scale, so much emphasis has not been conventionally placed thereon, and any particular countermeasure has not been suggested. However, with the spread application of color information, it has become indispensable to consider this respect.